JPS5825680Y2 - Shindou Kenshiyutsuki - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vibration detector for use in musical instruments such as guitars and violins, which has high sensitivity and features a frequency characteristic of sensitivity.

An example of a conventional vibration detector of this type will be explained with reference to FIGS. 1 and 2.

In the figure, 1 and 2 are piezoelectric ceramic plates installed in parallel inside a case 3 made of plastic or wood;
4 is the coaxial cable line, 4' is the core wire, 4'' is the ground wire,
Each of them is soldered to the electrode of the piezoelectric ceramic plate 1.

5 is a lead wire connecting the electrodes of the piezoelectric ceramic plates 1 and 2, and 6 is a filling adhesive such as epoxy resin or rubber resin filled in the gap in the case 3.

With this filling adhesive 6, the piezoelectric ceramic plate 1.2 is fixed to the case 3.
They are stored parallel to each other inside.

In the figure, A is the bottom surface of the case 3 located in a plane parallel to the planes of the piezoelectric ceramic plates 1 and 2, and is a vibration detection section.

This vibration detector is a device that converts the vibrations of the musical instrument into electrical signals by bringing the vibration detecting section A into contact with a musical instrument such as a guitar, violin, drum, or clarinet, either directly or via an adhesive or the like.

Therefore, by connecting this device to an amplifier and inputting its output signal to a speaker, it is possible to hear the small vibrations of the musical instrument as a loud sound.

The device can also be brought into contact with a machine to detect machine vibrations and convert them into electrical signals.

In a conventional vibration detector of this type, case 3 of vibration detection section A is used.
1 and 2 and the thickness of the filling adhesive 6 between the piezoelectric ceramic plates 1 and 2 and the inner wall of the case 3 are fairly uniform as shown in FIGS. 1 and 2, or as shown in FIG. 3. Thus, the thickness of the filling adhesive 6 had a simple slope.

Therefore, the sensitivity was low and the frequency characteristics were simple.

Note that the numbers and symbols shown in FIG. 3 are the same as in FIGS. 1 and 2, and dl and d2 refer to the piezoelectric ceramic plate 2 and case 3.
The thickness of the filling adhesive 6 between the inner wall and the inner wall is shown as dl>d2.

The present invention aims to provide a vibration detector that eliminates the above-mentioned conventional drawbacks.

An embodiment of the present invention will be described below with reference to FIGS. 4 and 5.

In the figure, 1 to 6 and A indicate the same parts as in the conventional example, and the vibration detector according to the present invention has grooves 7.7' and 8.8' near the periphery of the inner surface of the vibration detection part A of the case 3. It is provided.

Further, FIG. 6 shows other embodiments of the present invention.
6 and A are the same as before.

In this case, case 3 corresponds to approximately the center of the piezoelectric ceramic plate.
A recess 9 is provided on the inner surface of the vibration detection section A.

Further, FIG. 7 shows another embodiment of the present invention, in which 1 to 6 and A are the same as described above.

In the figure, 10 and 10' are spacers made of a relatively soft material such as rubber, soft plastic, cork, etc., 11 is a box-shaped metal foil for shielding, and the piezoelectric ceramic plate 1 is adhered to this. The adhesive surfaces are electrically conductive.

12, 13, and 13' are a convex portion and a concave portion provided in the vibration detecting portion A of the case 3.

That is, a piezoelectric ceramic plate 1 is attached to the inner surface of a box-shaped metal foil 11, and a plate-shaped or block-shaped spacer 10 made of rubber, cork, etc. is adhered to the gap with a filling adhesive 6, and a vibration detection unit having such a configuration is assembled. In this structure, a spacer 10' is fitted and bonded to the inner surface of a case 3 in which a protrusion 12 and a recess 13.degree. 13' are provided on the inner surface of the vibration detecting section A.

In the embodiment shown in FIG. 5, by providing grooves 7.7' and 8.8' near the periphery of the inner surface of the vibration detection part A of the case 3, the sensitivity in the low frequency band can be increased. .

At this time, when the material of the filling adhesive 6 is softer than the material of the case 3, the effect of increasing the sensitivity particularly in the low frequency band is remarkable.

Furthermore, in the embodiment of FIG. 6, the sensitivity is increased and the sensitivity in high frequency bands is also increased.

This effect is remarkable when the material of the filling adhesive 6 is softer than the material of the case 3.

In the embodiment of FIG. 7, the overall sensitivity is high and the sensitivity in the low frequency band is also higher.

This effect is remarkable when the material of the spacer 10, 10' is softer than the material of the case 3.

In each of the above-mentioned embodiments, a case has been described in which grooves and uneven portions are provided inside the vibration detection section A of the case 3, but the present invention provides similar effects even if they are provided outside of the vibration detection section A of the case 3. is obtained.

Further, even if the entire interior of the case 3 is not provided with fillers such as the filler adhesive 6 or the spacers 10, 10', the present invention can provide similar effects.

As described above, the present invention provides grooves or uneven parts on the inside or outside of the part of the case that corresponds to the vibration detection part, so that vibrations are effectively transmitted to the piezoelectric ceramic plate, resulting in higher sensitivity. Furthermore, by appropriately selecting the positions where the grooves and uneven portions are provided, the sensitivity in a specific frequency band can be increased.

Furthermore, by providing a convex portion on the vibration detection section at an appropriate position, sensitivity in a specific frequency band can be reduced.

Furthermore, a simple structure in which a filler made of a material softer than the material of the case is filled between the inside of the case and the piezoelectric ceramic plate can increase sensitivity and give distinctive frequency characteristics. It is of high industrial value, as it allows the production of highly sensitive products using only one sheet.

Of course, even if two piezoelectric ceramic plates are used, high sensitivity and characteristic frequency characteristics can be obtained, and this case is also within the scope of the present invention.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a vibration detector in a conventional example, Fig. 2 is a longitudinal sectional view of Fig. 1, Fig. 3 is a longitudinal sectional view of a vibration detector in another conventional example, and Fig. 4 is a longitudinal sectional view of a vibration detector of the present invention. FIG. 5 is a longitudinal sectional view of a vibration detector according to one embodiment, FIG. 5 is a longitudinal sectional side view of the same, and FIGS. 6 and 7 are longitudinal sectional views of a vibration detector according to other embodiments of the present invention. 1...Piezoelectric ceramic plate, 3...Case, 6
...Filling adhesive, 7.7', 8.8'...
...Groove, 9,13.13'...Recess, 10.1
0'...Spacer, 12...Protrusion.

Claims (1)

[Scope of utility model registration request] One side of the case is a vibration detecting section, grooves and uneven parts are provided on the inside or outside of this vibration detecting section, a piezoelectric ceramic plate is housed in the case, and a gap between the inside of the case and the piezoelectric ceramic plate is provided. In whole or in part, filled with adhesive or cork, rubber,
A vibration detector filled with a filler made of a material softer than the case described above, such as a spacer made of soft plastic.